中国物理B ›› 2022, Vol. 31 ›› Issue (2): 24103-024103.doi: 10.1088/1674-1056/ac422f

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Determine the physical mechanism and source region of beat wave modulation by changing the frequency of high-frequency waves

Zhe Guo(郭哲)1, Hanxian Fang(方涵先)1,†, and Farideh Honary2   

  1. 1 College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China;
    2 Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
  • 收稿日期:2021-09-08 修回日期:2021-12-03 接受日期:2021-12-11 出版日期:2022-01-13 发布日期:2022-01-25
  • 通讯作者: Hanxian Fang E-mail:fanghx@hit.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 41804149) and China Scholarship Council.

Determine the physical mechanism and source region of beat wave modulation by changing the frequency of high-frequency waves

Zhe Guo(郭哲)1, Hanxian Fang(方涵先)1,†, and Farideh Honary2   

  1. 1 College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China;
    2 Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
  • Received:2021-09-08 Revised:2021-12-03 Accepted:2021-12-11 Online:2022-01-13 Published:2022-01-25
  • Contact: Hanxian Fang E-mail:fanghx@hit.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 41804149) and China Scholarship Council.

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摘要： This paper introduces a new approach for the determination of the source region of beat wave (BW) modulation. This type of modulation is achieved by transmitting high-frequency (HF) continuous waves with a frequency difference f, where f is the frequency of modulated ELF/VLF (extremely low frequency/very low frequency) waves from two sub-arrays of a high power HF transmitter. Despite the advantages of BW modulation in terms of generating more stable ELF/VLF signal and high modulation efficiency, there exists a controversy on the physical mechanism of BW and its source region. In this paper, the two controversial theories, i.e., BW based on D-E region thermal nonlinearity and BW based on F region ponderomotive nonlinearity are examined for cases where each of these two theories exists exclusively or both of them exist simultaneously. According to the analysis and simulation results presented in this paper, it is found that the generated VLF signal amplitude exhibits significant variation as a function of HF frequency in different source regions. Therefore, this characteristic can be utilized as a potential new approach to determine the physical mechanism and source location of BW.

关键词: powerful HF waves, ionospheric modulated heating, beat wave modulation, ELF/VLF waves

Abstract: This paper introduces a new approach for the determination of the source region of beat wave (BW) modulation. This type of modulation is achieved by transmitting high-frequency (HF) continuous waves with a frequency difference f, where f is the frequency of modulated ELF/VLF (extremely low frequency/very low frequency) waves from two sub-arrays of a high power HF transmitter. Despite the advantages of BW modulation in terms of generating more stable ELF/VLF signal and high modulation efficiency, there exists a controversy on the physical mechanism of BW and its source region. In this paper, the two controversial theories, i.e., BW based on D-E region thermal nonlinearity and BW based on F region ponderomotive nonlinearity are examined for cases where each of these two theories exists exclusively or both of them exist simultaneously. According to the analysis and simulation results presented in this paper, it is found that the generated VLF signal amplitude exhibits significant variation as a function of HF frequency in different source regions. Therefore, this characteristic can be utilized as a potential new approach to determine the physical mechanism and source location of BW.

Key words: powerful HF waves, ionospheric modulated heating, beat wave modulation, ELF/VLF waves

中图分类号:  (Electromagnetic wave propagation; radiowave propagation)

  • 41.20.Jb
52.35.Mw (Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)) 94.20.Bb (Wave propagation) 94.05.Pt (Wave/wave, wave/particle interactions)